Changing Planet:
Permafrost Gas Leak

Background

Permafrost is frozen ground where the
temperature remains below freezing year around for two or more years. Permafrost
can have different characteristics and be found in different forms. It can
contain organic-rich soil or be sandy and rocky. It can even be solid rock. It
may contain frozen water or be relatively dry. But all permafrost has one important
characteristic in common; it is frozen. Global climate change is having an
impact on permafrost. Scientists are finding that permafrost is thawing to the
point that it is affecting people, wildlife and climate of the latitude
regions. Hidden in the frozen permafrost at many locations are large
quantities of organic matter, and if too much of the permafrost were to thaw,
then the subsequent decomposition of the organic matter by microbes could
release massive amounts of methane into the atmosphere. Methane has been
identified as a very powerful greenhouse gas which contributes to global
warming. In
this investigation, you will investigate the characteristics of permafrost, the
locations of permafrost and the correlation between thawing permafrost and
quantities of atmospheric methane.

Materials

Internet access

National Snow and Ice Data Center website

Google Earth & NSIDC Permafrost Layer

Arctic Portal Mapping tool

University of Alaska Permafrost Laboratory Site Layer

Methane data

Procedure

Part 1:

1. To gain an understanding of permafrost, log onto NSIDC:
All about Frozen Ground (http://nsidc.org/frozenground/index.html), and visit the
following sections of the website.

Answer these questions:

How does it form? (Be sure to define “active layer” in
your answer)

What affects it?

2. Also visit and briefly summarize the contents of these 2
sections of the website:

Climate and Frozen Ground

Studying Frozen Ground

4. Open the Arctic Portal Mapping tool (http://portal.inter-map.com)
and familiarize yourself with the layout of the tool. (see Figure 1)

Note that there is a Groups menu on the right of the page
and there are Data Layers in a menu sitting on top of the mapping tool. Take
10 minutes to practice using the tool by turning layers on and off, and
clicking on the information buttons that pop up on the map. Hold your mouse
over each of the tools at the top of the map to learn what you can do with
each. You can move around the two small menus on the map so that you can see
more of the map, and you can also enlarge the map to full screen. If you
gently hold your mouse over the various layers, the labels will appear.

5. To get started, turn on Boundaries in the Group menu and
Permafrost in the Data Layers menu. Use the icons to define the different
Arctic boundaries.

10°C July Isotherm:

AMAP Boundary line:

Arctic Circle:

CAFF Boundary line:

Tree line:

Click on the small "i" next to the permafrost
layer to bring up the definitions of the layers. Define the terms below:

Continuous Permafrost

Discontinuous Permafrost

Subsea Permafrost

Relict Permafrost

Sporadic Permafrost

Isolated Permafrost

6. Use the Arctic Portal to answer these questions focused
on Alaska. If you are unfamiliar with the shape of Alaska, use the Internet to
locate a map of Alaska.

Use the measuring tool to determine the distance in
kilometers of each boundary across the state of Alaska from the Gulf of Alaska
to the Beaufort Sea:

10°C July Isotherm: _____________________

AMAP Boundary line: ___________________

Arctic Circle: ________________________

CAFF Boundary line: ____________________

Tree line: ________________________

Which boundary covers most of Alaska? _____________________

Which boundary covers the most of Russia?
__________________________

7. Turn off all the boundary layers except the 10°C July
Isotherm, Tree line and the Arctic Circle.

What type of permafrost is predominant above these lines?
___________________________________

Why do you think this is so?

Turn off the permafrost layer and turn on the vegetation
layer. What type of vegetation can be found in this region?

Turn the vegetation unit layer off and the permafrost layer
back on. As you move to the Gulf of Alaska, what type of permafrost is
predominant in this region?

8. Use this map tool to investigate other layers while
focusing on Alaska. Describe your findings here:

Other layer investigated:
____________________________________

Pattern found in Alaska:

Part 2

1. Open Google Earth and access the permafrost layer from
the National Snow and Ice Data Center (NSIDC). (see Figure 2)

2. What type of permafrost can be found in the lower 48
states? __________

In which states can it be found?

Why do you think the permafrost is found only in these
locations?

3. Note that now you can see the subsea permafrost.

Which country bordering the Arctic has the greatest amount
of permafrost? ______________________

Adjacent to which country can the most subsea permafrost be
found? ___________________________

Use the measuring tool to measure in kilometers the extent
of the subsea permafrost from northern Alaska into the Beaufort Sea.

How far does the subsea permafrost extend into the Beaufort
Sea? __________________________ km

4. Open the University of Alaska Permafrost Laboratory Site
Layer in Google Earth Map while the NSIDC permafrost layer is open to explore
borehole data that has been collected over long periods of time. (see Figure 3)

Figure 3: Screenshot of Google Earth with the
Permafrost Laboratory Site open.

Boreholes are used to measure the temperature of the permafrost.
Notice the transect of borehole sites across the state of Alaska. Why do you
think the scientists placed the boreholes at these locations?

5. Figure 4 below is an example of the type of graph you
will be interpreting for select borehole sites. Each site was visited once
during the summer and electronic temperature sensors were used to collect
temperature data at numerous depths. To practice interpreting the data, answer
the questions below.

How many years are represented by this data?
__________________________

The data appears to follow a similar trend over the years,
although there are subtle variations.

In 1993 what was the temperature at 5m below the surface?
_____________

In 2010 what was the temperature at 5m below the surface?
_____________

In 1993 what was the temperature at 10m below the surface?
_____________

In 2010 what was the temperature at 10m below the surface?
_____________

6. Locate the boreholes in Google Earth and fill in the
table with data from these locations. While
you are using Google Earth look at the pictures taken at these sites to get a
sense of what the landscape looks like in the Polar Regions.

Location

Borehole Depth (m)

Latitude

Longitude

Type of Permafrost

Yukon Bridge (YB1)

Elevation: 221m

61

Galbraith Lake(GL1)

Elevation: 823m

75

Franklin Bluffs Borehole
(FB1)

Elevation: 33m

60

Use the handout with the permafrost borehole data or the
data from the Google Earth layer to extract the temperatures (°C) at these
depths for the years listed.

Year

Yukon Bridge

Galbraith Lake

Franklin Bluffs Borehole

5m

10m

20m

5m

10m

20m

5m

10m

20m

1995

1996

1997

1998

1999

2005

2006

2008

2009

2010

7. Carefully analyze the data for trends with depth at each
location. Has the permafrost warmed, cooled, or stayed the same in each of the
time periods?

5m

10m

20m

Yukon Bridge

1995-1999

2005-2010

Galbraith Lake

1995-1999

2005-2010

Franklin Bluffs Borehole

1995-1999

2005-2010

8. Summarize your findings from the table. What other
datasets could you use to investigate the above data further? Why?

Part 3

Climate models projecting into the future show that as global
temperatures rise large quantities of the current permafrost will thaw. (see
Figure 5)

Figure 5:The averages of the scenarios in the
Arctic Climate Impact Assessment (ACIA) are presented in this figure, for the
year 2090, with the surface temperatures over land, the size of the polar ice
cap, and the outer limits of permafrost.

(This graphic was created by Hugo Ahlenius, UNEP/GRID-Arendal
using data from ACIA. Acquired from http://maps.grida.no/go/graphic/projected-changes-in-the-arctic-climate-2090)

Buried below much of the oxygen poor permafrost is organic
matter. As temperatures in Arctic rise and the permafrost thaws the organic
matter will go through anaerobic decomposition releasing methane into the
atmosphere as a by-product. Methane is a powerful greenhouse gas. Although
there is much less methane in the atmosphere than carbon dioxide, it traps heat
about thirty times as efficiently as carbon dioxide. There are two origins of
methane in the Arctic: 1) trapped within the ice crystals found in deep
locations of high pressure and low temperatures; and 2) in organic matter
frozen in the permafrost.

1. There is an annual fluctuation in the quantity of
methane at this location where the quantities are higher in the fall and winter
months and lower in the summer months. Why do you think this is so?

2. What is the overall trend in this data?

3. What is the trend in the data for dates represented in
Part 2 of this lesson?

4. Within this you utilized only two sets of data. What
other datasets would assist you in correlating the changing temperatures of the
permafrost with the changing levels of atmospheric methane? Explain your
rationale for selecting these other datasets.

Application

1. Think about the reservoirs, sources, and sinks within
the carbon cycle along with the role of photosynthesis, and the northern
hemispheric distribution of photosynthetic organisms. Use the space below to
outline a sequence of events that would occur should the permafrost continue to
thaw and release large quantities of methane into the atmosphere. Keep in mind
that the Arctic currently takes in more carbon than it releases, and therefore
is a carbon sink. Use the resources from this lesson to support your
discussion. Revisit the NSIDC Frozen Ground website for further assistance.